Habitat/ecology: Dry forest, roadsides, moist forest, rainforest openings at low elevations. "C. madagascariensis occurs over a wide latitudinal range in western Madagascar with annual rainfall between 600 and 1800 mm. Plants occur naturally in riverine and seasonally flooded forests. The weedy aggressiveness of this species has been favored by the widespread destruction of forests and it may be dominant in many disturbed situations. It is common on hillsides and along gullies in the secondary savannahs which dominate western Madagascar" (Marohasy and Forster, 1991; pp. 575-576).